Fans for process heating applications are chosen on the basis of whether a positive-pressure (forced draft or FD), negative-pressure (induced draft or ID) or balanced-draft system is required. ID fans are required to handle heated air passing through the fan and must therefore be constructed to perform reliably at higher temperatures, particularly with respect to the bearings.

Care in selecting the impeller, materials of construction and additional features is essential to ensure the smooth airflow and reliability that is demanded.

The fan commonly requires additional components, including silencers and filters, safety features such as guarding and isolators, dampers or inlet guide vanes for improved efficiency.